textproduct: Rapid City

KEY MESSAGES

- Southwest flow aloft expected through the weekend with showers/thunderstorms possible Friday.

- Upper trough moves through for early next week bringing increasing precipitation chances Sunday night onward.

- Temperatures will be 5-10F above normal through the weekend and then back to seasonal readings early next week.

UPDATE

Issued at 1038 PM MDT Wed Sep 23 2026

Lingering showers and an isolated thunderstorm will continue tonight across portions of the central South Dakota plains. Otherwise, conditions will continue to clear out from west to east. A few patches of fog cannot be ruled out in far eastern portions of our CWA, although support among the guidance is pretty limited. Reworked PoPs/QPF overnight and Thursday, but no other significant forecast changes were needed.

DISCUSSION

(This Evening Through Wednesday) Issued at 100 PM MDT Wed Sep 23 2026

18z surface analysis had warm front from weak low over southeast MT into eastern CO. Ahead of it, quite a bit of cloud cover persists. Behind it, clearing skies per 0.5km visible satellite loop. These features in association with shortwave trough moving across eastern MT/western ND per water vapour loop. 90kt streak overhead. Effects of these features the main short term forecast concern.

Later this afternoon/evening, early Fall solar insolation should erase MLCIN from the 18z KUDX sounding with surface temperatures around 80F needed. ~1KJ/kg MLCAPE will be available along the warm front with 40kts of effective shear under jet streak. Convection should develop after 21z per most CAMs with isolated strong/severe thunderstorms possible creating marginally severe hail/wind gusts. Activity will move east this evening with clearing skies over the CWA overnight. Temperatures will be near guidance.

Shortwave ridging Thursday will bring dry weather for most of the CWA, but aforementioned warm front gets hung up over the SD/NE border which may be the focus for a few shra/TS. Stronger wave arrives Friday with increasing PoPs, especially east of the Black Hills where best low level moisture return/buoyancy forecast. Dry Saturday and most of Sunday. Temperatures will be 5-10F above normal through the weekend. Then, ensemble guidance portrays a strong upper trough slicing across the northern Plains with increasing chances of precipitation as well as cooler, more fall- like temperatures.

AVIATION

(For the 12Z TAFS Through 12Z Friday Morning) Issued At 537 AM MDT Thu Sep 24 2026

Patchy fog is moving into central SD early this morning. For the TAF sites, VFR conditions are expected through the period with only small changes expected in wind direction and speed.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.